| Soil salinization is one of the major abiotic factors that seriously affectsthe growth and development of plant and the productivety of crop.Previous studies have shown that sainfoin?Onobrychis viciaefolia Scop.?displayed the lower ability to toletant salt,especially at its the seedling stage,which is extremely sensitive to high salt.Therefore,it is very necessary to cultivate new varieties and/or lines of sainfoin with strong salt-,alkali-or saline-alkali-tolerance,which is of great significance to the sustainable development of animal husbandry and the improvement and utilization of saline land in northwest China.In view of this,this study used sainfoin as the material to explore the factors affecting its tissue culture regeneration system and its physiological response to salt stress and saline-alkali stress.The results obtained are as follows:1.High-salt stress significantly inhibited the growth of sainfoin seedlings compared to the control.However,the addition of different concentrations of KCl clearly ameliorated the inhibition of high-salt stress on growth of seedlings.It was observed that under high-salt stress,with the increase of KCl concentrations,fresh weight,dry weight,tissues water and total chlorophyll contents showed the gradually increased trends and reach the greatest values when concentration was 25 mmol·L-1,then and slowly decreased;Na+concentrations in both shoots and roots displayed the gradual reduction,while K+concentrations and K+/Na+ratios had the remarkably increased trends;Proline,soluble sugar and soluble protein contents reached the peak values when concentration of KCl was 25 mmol·L-1,then and gradually reduced;Malondialdehyde?MDA?content,and cell wall,cytoplasmic and vacuolar invertase activities exhibited the clearly decreased trends,while superoxidase?SOD?,catalase?CAT?,ascorbate peroxidase?APX?,sucrose synthase?SS?and sucrose phosphate synthase?SPS?activities,sucrose and glucose contents showed the gradually increased trends.Taken together,our results suggested that the addition of K+alleviates high-salt toxicity to sainfoin seedlings by maintaining K+and Na+homeostasis,enhancing antioxidant enzymes activities,and improving sucrose synthesis and accumulation in shoot.2.Under alkaline stress and saline-alkali stress,the fresh weight,dry weight and tissue water content of sainfoin seedlings were significantly decreased compared with the control;the Na+accumulation in the plant was increased,and tconcemtration of K+,ratio of K+/Na+,contents of proline,soluble sugarcontent and chlorophyll were significantly decreased;while content of MDA was greatly increased,and activity of antioxidant enzyme was weakened.Additionally,the content sucrose,glucose and fructose and the activities of SS,SPS neutral invertase and acid invertase were siginificantly decreased by alkaline stress and saline-alkali stress compared to control.These results indicated that high alkali stress and salt-alkaline combined stress had toxic effects on the sainfoin and inhibited its normal growth and development.3.The seed germination rate in MS medium was higher than that in 1/2 and 1/4 MS medium,and the germination rate went up to 88.9%with the pretreatment of 4?refrigeration.Different hormones combinations show have different effects on callus induction,adventitious shoot inducing and rooting culture indifferent organs.The results showed that the callus induction rate of hypocotyl is the highest in medium mixed with MS+0.5 mg·L-11 6-BA+1.0 mg·L-11 NAA,and the induction rate was 87.3%;Adventitious bud induction medium was MS-added 6-BA+NAA,or MS was added with 6-BA+IBA;The best effect of adventitious bud proliferation was MS plus 0.05%activated carbon and 1.0 mg·L-16-BA and 0.5 mg·L-11 IBA.The best method for rooting is the filter paper bridge method.The specific medium formula is 1/2 MS+1.0 mg·L-1IBA+0.1 mg·L-1NAA?... |
PDF Full Text Request